A thermo-electric 3-D analysis of 980nm vertical cavity surface emitting laser (VCSEL) arrays based on the finite element method (FEM) is presented in this paper. High performance VCSEL array structures with square mesas are modeled by applying a steady-state 3-D heat dissipation model. Several oxide aperture diameters (D a ), substrate thicknesses, current densities, array sizes, heat flux, and temperature profiles are considered. The analysis shows that the maximum internal temperature of a VCSEL array ranges from 306.5K for a 20μm D a , 100μm substrate thickness, 666A/cm 2 current density, and a 1×1 array size to 412K for a 5μm D a , 300μm substrate thickness, 1200A/cm 2 current density, and a 4×4 array size.